Core box clamp for core making machines



oct.. 7, 1941.

w.A E. NAYLoR Filed July 27, 1940 2 Sheets-Sheet l Oct. 7, 1941.

w. E. NAYLo 2,258,466

coRE B'ox CLAMP FOR coRE MAKING uAcHINEfs Filed July 27, 1940 2Sheets-Sheet 2 spreading sidewise.

Patented Oct. 7, 1941 UNITED STATES PATENTvv OFFICE CORE BOX CLAMP FORCORE MACHINES MAKNG 4Walter E.. Naylor, chicago, 111., assign toChampion Foundry & Machine Company, Chicago,

Ill., a corporation of Illinois Application'July 27, 1940, Serial No.347,829

3 Claims.

` This invention relates to machines for makving sand cores, and moreparticularly to machines of that type in which the sand that forms the"core is blown into the core-box or mold by airv under pressure. Thesemachines are usually provided ,with an air chamber and a movable sandtransfer member which carries a charge of sand at least sufficient tomake the core from a -supply hopper to a position in alinement with4into the core-box and packed therein by the air I and sand under'highpressure.

The lift Vis then lowered, and the core-box and core removed.

For convenience in removing the nished core,

most core boxes are made in mating halves, divided either vertically orhorizontally; and,

4wherethe box is designed to mold a `tapered core,

it is usually made in a single piece having a tapered cavity,` it beingpractical to remove the finished tapered core from'the box by merelylifting the latter off the core. During the blowing operation theinterior of the core-box is -under a high pressure, often as high as 130pounds per square inch. If the core box is dvi'ded horizontally, the twosections of the box are maintainedl closed on each other by the upwardthrust of the lift on the `lower section and `the opposeddownward'thrust of the sand transvter member on the upper section, andno lateral supports are required to prevent the box'from Where, however,the corebox isdivided vertically, either the two sections ofthe box mustbe securely clamped together, or

Vlateral supports for the twosections are necessary to preventspreadingof the sections during Vthe-.blowing operation.- .The application andremoval of clamps involves' cons`iderable time on the .part of theoperator; and, consequently, to speed up 'thel operation of core making,heretoforerthe" core box has been flanked on one `side by aiixed'vertical wall on the platform, and during `theblowing vofthe core'the other side'of the box` has beenfsubjected to athrust suiiicient to.prevent spreadingrof the box under its internal pressure. So far `asIam aware', the means hereto-iore used iorlaterallyclamping the core-boxduring theblowing operation has consistedof a Fig. 1. i

plunger directly actuated by compressed air usually from the same sourcethat suppliesv pressure to actuate the vertical lift or jack. Unlesssuch plunger has a very large area subjected to the air pressure, whichmakes' it clumsy and cumbersome, it is inadequate to resist the internalspreading pressure to which the core-box is subjected, and thissometimes imposes an undesirable limitation on the air pressure whichcan be used in the blowing operation, in order to avoid accidents intheY making of the cores through spreading of the two core boxsections.

The main object of the present invention has been to provide animprovement onY the means "heretofore used for laterally compressing orclamping a verticallydivided core box; and, as will hereinafter fullyappear, this improvement is based on the principle of the hydraulicpress, through the use of which thepressure afforded by a body ofcompressed air, which may be at the same pressure as that used in thepneumatic jack or lift, operating in an` air cylinder" of relativelyVsmall diameter, is greatly multiplied through a body of liquid such asoil or water of much larger 'area acting directly upon one or moreplungers that exert a direct thrust on the side of the core box; thearea of such plunger or plungers being greatly in excess of the area ofthe pneumatically operated plunger of an hy- `draulic pump whichtransmits pressure to the confined body of liquid'in the hydraulicpress.

4In order thatthe invention, its novel 'structuralfeature's and its modeof operation, may be clearly understood, Ihave, in the accompanyingdrawings, illustrated one practical embodiment thereof which, inpractice has been found to satisfactorily effectuate the stated objectofv the invention. Referring to the drawings- I Fig. lis airontelevation of such parts of a known core making machine as cooperate withmy improved core-box clamp, certain parts of the latter'being shown invertical section.

Ylig. 2 is a top plan view, on the'line 2*-,2 of

Fig. 3 is a vertical section, mainly through the oii chamber and ramsofthe hydraulic press, `taken on the line 3--3 of Fig. 4. Fig. i is avertical transverse section, taken Fig. 5 is an `enlarged verticalsection through the lower portion ofthe hydraulic pump which appliespressure to the oil in the main oil charnber ofthe hydraulic press. ,Y

in the drawings, "I 0 indicates diagrammatically a casting containing avalve controlled air chamber, communicating with a source of compressedair, and into which the air blast for blowing the sand into the core-boxis admitted. The lower end of this air chamber is adapted to registerwith the upper end of a sand carrier designated by II which, in commonpractice, is laterally shiftable between the discharge end of a sandhopper and its position in register with the air chamber I0. Underlyingthe sand carrier II is a platform I2, that is mounted on the upper endof a cylinder I3 that slidably telescopes over a fixed plunger I4supported on a base I5. The platform I 2 forms a support for a core-box,that, just prior to the blowing operation, is raised by the platform I2into tight engagement with the sand discharge grid in the bottom of thesand carrier II; the platform and core-box being raised by compressedair admitted between the movable platform and the upper end of the xedplunger I4.

The parts thus far described are well known parts in the core makingmachine art.

I have herein illustrated the above described parts as cooperating witha vertically divided core-box, comprising two mating sections I6 and I1,the line of division being indicated at I8. Flanking the section I1 is aheavy abutment member I9 formed with a base 20 secured to the platformI2 as by cap screws 2l. As shown in Fig. 2, the screws 2I may passthrough longitudinal slots 22 in the base 20, to adjust the apparatus tocore-boxes of varying widths.

Flanking the outer side of the other section I6 of the core-box'isanhydraulic press designated as an entirety by23. AThe preferredstructural features of this press are best illustrated in Figs. 3 and 4.It includes a fixed member 24 preferably of circular cross-section andhaving an integral base 25 that is adjustably secured to the top of theplatform I2 by screws 26 and slots 21, as in the case of the abutmentI9. It also in cludes a movable member designated as an entirety by 28,and comprising a circular head 29 that telescopes over theV adjacent endof the fixed member 24, a ribbed shank 30, and a foot 3l which bearsdirectly on the outer side of the core-box sectionv I6. Between theoverlapping parts 29 and 24 there is inserted a packing ring 32 forexcluding sand from the interior of the press. The fixed Amember 24 iscast with an internal transverse skeleton web designated by 33, andthrough this web are formed a group (herein shown as four) of holes inwhich are fitted circular linings 34 for a corresponding number ofslidable rains 35, symmetrically grouped around the axis of the fixedmember 24. These rams 35 at their outer ends contact the head 29 of themovable member 28 of the press, as clearly shown in Fig. 3; and lying incontact with the inner ends ofthe rams are cup-shaped washers 36, thatare pressed against the rams by thrust springs 31 encircling studs 3,8mounted in the end wa of the fixed member 24.

The movable member 28 of the press is constantly urged toward itscooperating fixed mem- 'ber 24 by the following means. 39 designateseach of a group of rods that are mounted in the head 29 of the movablemember and extend through holes in the web-33 and the end wall of thexed member 24, and project beyond the lat- 'ter as shown at 39. On theouter ends of the projections 39 are heads 40, and encirclingtheprojections 39 and confined endwiseunder tension between the heads 40and the end wall of the festly, these springs act to automaticallyretract the movable press member 28 from the core-box, to release thelatter, after the blowing operation has been completed, so that thecore-box may be readily removed and opened.

Within the fixed member 24, between its end wall and web 33 is a chamber42 that is completely lled by a body of liquid, preferably oil. In thecircumferential wall of chamber 42 is a port 43 (Fig. 3) closed by aremovable plug 44, through which oil can be introduced to charge thechamber 42 or to replace losses through leakage.

Describing next the power means for operating the hydraulic press, 45(Fig. 1) designates the y cylinder of a'pneumatic motor that may be hungfixed member 24 are .thrustsprings 4I. -Mani- 75 lfrom one end of thplatform I2, and in this cylinder a piston 46, to the underside of whichis secured the narrow plunger 41 of an hydraulic pump, that works in acylinder 48 depending from the lower head of the pneumatic cylinder 45.The lower discharge end of the pump cylinder 48 communicates by a hose49 with the liquid chamber 42 of the hydraulic press, as clearly shownin Fig. 3. I'he piston 46 of the pneumatic motor is forced downwardly bycompressed air admitted above the same, and is returned by a. spring 50.To provide for the back ow of the necessary small quantity of oil whenthe hydraulic press is collapsed, the cylinder 48 of the hydraulic pumpis encircled by a small oil well 5I that is ported at its lower end asshown at 52 (Fig. 5) to the discharge end of the hydraulic pump cylinder48. On the lower end of the plunger 41 of the hydraulic pump is acupwasher 53, best shown in Fig. 5, that is held in place against theplunger by a spring 54.

o Compressed air for operating both the corebox lift and the core-boxclamp may be supplied from a suitable source through a hose 55 (Fig. 1),in which is included a two-way cock 56 for admitting and exhausting themotive fluid. To this air line 55 are connected, beyond the cock 56, abranch hose 51 leading to the pneumatic motor 45 which operates the pumpof the hydraulic press, and another branch hose 58 leading to thepneumatic motor I3 which raises the core-box into engagement with thesand carrier. In machines where the raising of the core-box intoregister with the sand. carrier automatically opens the sand blow valve(which is usually the case) it is essential to operate the hydraulicpress to clamp the core-box laterally, before raising the core-box toreceive the san-d blast. For this purpose I have provided in the airsupply line means by which the hydraulic pump that supplies pressure tothe hydraulic press is actuated in advance of the pneumatic lift whichraises Vthe core-box. This means preferably consists of what is known asa sequence valve indicated as an entirety by 59 that is introduced inthe branch line 58. This sequence valve partly throttles and slows downthe air owing to the air lift through line 58 relatively to that flowingthrough line 51 to the air motor of the hydraulic pump, so that thelatter is first actuated to effect the clamping ofthe core-box, and thecore-box lift is actuated jimmediately thereafter. This se- 4,quencevalve4 Y59 is a known commercial valve,

and no claim thereto per se is made herein.` It includes an upper valve60 pressed -to its seat by a spring 6I, which is opened by differentialpressure Von a piston'62 connected to the valve stem 63,when the air isturned on, the valve 60 partially' throttling the air flow. It alsoincludes a lower ball valve 64 lightly held to its seat by a spring 65,which provides a return for the exhaust of the pneumatic lift I3 whenthe core box is lowered.

The description of the operation has been to a considerable extentindicated in connection with the description of the structure, but maybe briefly summarized as follows:

When the empty core-box has been placed on the platform I2 in registerwith the discharge from the sand carrier II, the valve 55 is turned tothe position shown in Fig. 1, and compressed air flows iirst to thepneumatic cylinder 45 actuating the hydraulic pump and causing thehydraulic press to clamp the core-box. An instant later compressed airreaches the air lift and raises the closed core-box into sealedregistration with the sand carrier II, and this turns on the air blast,filling the core-box with densely packed sand, thus making the core.This position of the parts is illustrated in Fig. 1. The valve 56 isthen given a quarter turn clockwise viewing Fig. l, and this places bothbranch lines 51 and 58 in communication with an exhaust port 55 in thecasing of the Valve 56, providing for the exhaust of both pneumaticmotors. The cylinder I3 of the pneumatic lift, the platform I 2, and thehydraulic press and core-box descend, and at the same time the piston 46is raised to its high position by the spring 50. The springs 4I at thesame time act to retract the movable member 28 of the hydraulic pressfrom the corebox, so that the latter may be readily removed and replacedby the next empty core-box to be filled by a repetition of the samecycle. It may here be stated that both the rising and lowering movementsof the platform and core-box and the in-and-out movements of thecore-box engaging member of the hydraulic press are but a small fractionof an inch, and this very small required compressive and releasemovement on the corebox is one reason that makes the use of an hydraulicpress to clamp the core-box thoroughly practical in a machine of thischaracter.

Variations and modifications in the details of structure and arrangementfrom those herein shown and described may be resorted to Withoutdeparting from the substance of the invention as defined in thefollowing claims.

I claim:

1. In a core-box clamp of the type described, the combination with asand transfer member, a platform beneath said transfer member to supporta divided core-box, and a pneumatic motor for raising said platform toforce the corebox into snug contact with said transfer member, of anhydraulic press mounted on said platform engaged with one side of saidcore-box, a fixed abutment on said platform engaged with the oppositeside of said core-box, an hydraulic pump communicating on its dischargeside with the liquid chamber of said hydraulic press, a pneumatic motorfor actuating said hydraulic pump, a compressed air supply line havingbranches respectively serving said pneumatic motors, and a cock in saidair supply line for admitting and exhausting compressed air to and fromsaid branches.

2. In a core-box clamp of the type described, the combination with asand transfer member, a platform beneath said transfer member to supporta divided core-box, and a pneumatic motor for raising said platform toforce the core-box into snug contact with said transfer member, of anhydraulic press mounted on said platform engaged with one side of saidcore-box, a fixed abutment on said platform engaged with the oppositeside of said core-box, an hydraulic pump communicating on its dischargeside with the liquid chamber of said hydraulic press, a pneumatic motorfor actuating saidhydraulic pump, a compressed air supply line havingbranches respectively serving said pneumatic motors, means in one ofsaid branches for effecting actuation of the hydraulic pump motor inadvance of the actuation of the platform raising motor, and a cock insaid air supply line for admitting and exhausting compressed air to andfrom said branches.

3. In a core-box clamp of the type described, the combination with asand transfer member, a platform beneath said transfer member to supporta divided core-box, and a pneumatic motor for raising said platform toforce the core-box into snug contact with said transfer member, of anhydraulic press mounted on said platform engaged with one side of saidcore-box, a fixed abutment on said platform engaged with the oppositeside of said core-box, an hydraulic pump communicating on its dischargeside with the liquid chamber of said hydraulic press, a pneumatic motorfor actuating said hydraulic pump, a compressed air supply line havingbranches respectively serving said pneumatic motors, a sequence valve inthe branch serving the platform raising m'otor, and a cock in said airsupply line for admitting and exhausting compressed air to and from saidbranches.

WALTER E. NAYLOR.

